In A History and Theory of Informed Consent (1986), Beauchamp and Faden subordinate justice to autonomy and beneficence, asserting that issues of informed consent are not fundamentally problems of social justice. In the era of Big Data and AI-driven medicine, this principlist framework is inadequate. Medical data serves as a critical resource in precision medicine and genomics, yet its collection and use may exacerbate health inequities. Traditional autonomy-based informed consent is ill-suited to the scale and complexity of Big Data, where meaningful individual consent becomes impractical. Instead, an alternative framework grounded in Christian ethics, particularly agape-centred justice is needed. This paper argues that a justice-centred approach to data governance - modelled on collective responsibility rather than individual choice - better aligns with Christian commitments to human flourishing. The best-known example could be Reinhold Niebuhr's Christian Realism, which emphasises solidarity, the common good, and balancing power. He criticises the liberal assumption of principlism that individuals are purely rational agents capable of autonomous decision-making, instead arguing that they are shaped by power structures and bound by social obligations. Justice is the earthly expression of agape and as such ensures that collective structures lessen, rather than worsen, inequality. The principlist model of autonomy-based informed consent is inadequate in the context of Big Data as it assumes that individuals have equal power to negotiate their data rights, but an agape-centred justice framework shows that this is not true in practice, as structural injustices and power imbalances prevent truly free participation. This paper calls for a reconsideration of principlism's dominance in bioethics through the lens of Christian justice, particularly questioning autonomy's role in medical Big Data as data governance increasingly shapes health outcomes.